Drugs are often administered to patients from containers that include more than a single dose of the drug. Certain known drug delivery containers enable patient or provider control of or measurement of the dose of the drug delivered from such containers to allow delivery of less than all of the drug in the container at a particular time. For example, cough syrup is typically packaged and sold in a 4 fluid ounce bottle containing nearly 12 doses of 2 teaspoons each. To administer the cough syrup, the medicine is poured into a teaspoon or a cup having graduated markings along the sides of the cup to measure the amount of medicine that equals a teaspoon. Another example is a syringe which contains more volume of a drug than the volume of a single dose to be administered by a provider to the patient. For example, 10 ml of a drug may be provided in a 10 cc syringe when only 1 cc is to be administered to the patient. Graduated markings indicating volume within the syringe enables the provider to know how far to push the plunger of the syringe to deliver 1 cc of the drug to the patient. Another known example is an infusion pump. Infusion pumps are typically configured to pump a precisely measured aliquot of a drug from a larger volume of the drug typically provided in an IV bag. Each of these examples enable the health care provider to administer a defined amount or metered dose of the drug and to track, record and account for how much of the drug was delivered to the patient.
Other drug delivery mechanisms provide much more limited control of, and variability in, the amount of drug delivered from dose to dose. For example, drugs administered as aerosols or sprays are typically pressurized or pumped from a container containing multiple doses of the drug. Administration of a drug using these types of mechanisms can result in substantial variability between delivered doses and an inability to know for certain how much drug is delivered to a patient. For example, in aerosol or spray containers, air may replace the drug as a portion of the drug in the container is released or pumped from the container resulting in less than the desired amount or a different amount of the drug being delivered from dose to dose. Also, a provider may actuate or depress the release mechanism a different number of times or may not keep track of the number of times the release mechanism is actuated or depressed when delivering the drug to a patient or themselves. Furthermore, the provider may only partially actuate or depress the release mechanism or may actuate or depress the release mechanism to a different extent for each delivery of the drug. Such variability between doses and an inability to document how much of a drug is actually delivered to a patient may expose the patient to unnecessary risks such as overdose (and thus less efficiency), side effects, densensitization to the drug and the like. There is therefore a need for improved drug delivery devices.